New Shell gas?
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Svart
Well-known member
I dunno but I've rebuilt about a dozen engines over the years, both new and old, foreign and domestic. I've never actually seen an engine with those crazy carbon deposits that you see in the ads for the cleaning additives..
i just think it's another marketing gimmick really. Anybody who knows about the "old" engine/injector cleaners knows that most of them are just kerosene but yet people swear by certain brands and whatnot.
The real trick would be to prove that this new chemical works.. How would "average Joe" know if it's working or not?
i just think it's another marketing gimmick really. Anybody who knows about the "old" engine/injector cleaners knows that most of them are just kerosene but yet people swear by certain brands and whatnot.
The real trick would be to prove that this new chemical works.. How would "average Joe" know if it's working or not?
I'd be far more worried about them mandating higher percentages of ethanol,, which does nasty stuff. Nitrogen seems relatively harmless, in comparison.
JR
JR
SSLtech
Well-known member
Well... a direct-injection engine WILL.Svart said:
In most motors, the port injection washes the valves. In TDI and FSI direct-injected motors, the valve stems never get washed.
But Nitrogen is snake-oil right now. -Look at the claims for filling your tires with it. Your lungs are already almost 80% full of it, but nobody ever realises that.
Keith
> Anyone know what this is about?
I doubt any of us here is chemist-enough to fully understand it.
Straight Nitrogen is pretty inert.
But the PR says "Nitrogen is a key element of the active cleaning molecule.."... it's not just straight Nitrogen (would not stay in the liquid anyway).
Nitrogen compounds run from NOx which irritate the lungs, to Ammonia NH3 which is good for cleaning glass, also tobacco stain, to ammonium nitrate NH4NO3 which aside from being good fertilizer can be used in a formula to "clean" rock and buildings (coal-mining, Oklahoma City bomb).
So where did they stick that N? Is it an actual change in engine fuel? Or did the PR department take a small riff and blow it up into a fugue?
One particular point: Pure Nitrogen is quite inert at normal temperature but DOES get active at high temperature, and specifically at engine combustion temperature. The "NOx" in your smog-ticket is just atmospheric N and O plus about 1,400 deg heat. Since NOx was a major problem in Los Angeles circa 1960, engine controls seek to limit peak combustion temperature. Even though a heat-engine should peak as hot as the pistons can stand, NOx production limits what we can accept. Conversely, maybe Shell has found an N-molecule which is passive until it meets the combustion.
> I wonder what it will do to older car engines and cats
Not real worried. Surely Shell chemists (some of the world's best) know what they are doing. Shell would not offer it so generally if there was risk of real harm.
"tested ... more than a half-million miles ... newer vehicles with low mileage, and older vehicles with high mileage."
> i just think it's another marketing gimmick really.
Yes. You take a little feature like olive-oil coupling-caps, and blow it up into an Audio Revolution. Hey, most products ARE awful dull, change little from one year to the next. Those PR guys have to find excitement where they can.
> I've never actually seen an engine with those crazy carbon deposits
I have. But I've never seen enough carbon in the chamber to increase compression ratio significantly, although that was a problem in the 1920s. You can have a flake of carbon initiate pinging; but with modern fuels on older engines, a few full-bore bursts usually burns it off. Never seen so much carbon on a valve that it would reduce airflow. I sure have seen 1960s engines so full of OIL sludge that they had major problems... but that's not really a gasoline thing.
Apparently it can happen that fuel injectors lose capacity. On any modern ECU car, up to a point, this is corrected by the ECU applying longer injection pulses to get a happy tailpipe mix. When the nozzle gets real-clogged, the ECU can't make happy-mix at full throttle high RPM... then it will set the Check Engine light and you will fail your next smog-inspection.
But seems to me that clogged injectors are the Gas Company's Problem. Actually the way they make gasoline now the stuff is probably very-very-clean at the refinery. But crud sneaks in throughout the distribution process. Heck, I've seen used oil poured into the gasoline tanks; even done it myself. So gasoline company detergents are self-defense against their own distribution problems.
I would not cross the street to buy, or not-buy, Shell.
I do try to buy where the station appears to be tightly controlled by a major oil company. Sloppy dirty may be a little more likely at the no-name stations.
I doubt any of us here is chemist-enough to fully understand it.
Straight Nitrogen is pretty inert.
But the PR says "Nitrogen is a key element of the active cleaning molecule.."... it's not just straight Nitrogen (would not stay in the liquid anyway).
Nitrogen compounds run from NOx which irritate the lungs, to Ammonia NH3 which is good for cleaning glass, also tobacco stain, to ammonium nitrate NH4NO3 which aside from being good fertilizer can be used in a formula to "clean" rock and buildings (coal-mining, Oklahoma City bomb).
So where did they stick that N? Is it an actual change in engine fuel? Or did the PR department take a small riff and blow it up into a fugue?
One particular point: Pure Nitrogen is quite inert at normal temperature but DOES get active at high temperature, and specifically at engine combustion temperature. The "NOx" in your smog-ticket is just atmospheric N and O plus about 1,400 deg heat. Since NOx was a major problem in Los Angeles circa 1960, engine controls seek to limit peak combustion temperature. Even though a heat-engine should peak as hot as the pistons can stand, NOx production limits what we can accept. Conversely, maybe Shell has found an N-molecule which is passive until it meets the combustion.
> I wonder what it will do to older car engines and cats
Not real worried. Surely Shell chemists (some of the world's best) know what they are doing. Shell would not offer it so generally if there was risk of real harm.
"tested ... more than a half-million miles ... newer vehicles with low mileage, and older vehicles with high mileage."
> i just think it's another marketing gimmick really.
Yes. You take a little feature like olive-oil coupling-caps, and blow it up into an Audio Revolution. Hey, most products ARE awful dull, change little from one year to the next. Those PR guys have to find excitement where they can.
> I've never actually seen an engine with those crazy carbon deposits
I have. But I've never seen enough carbon in the chamber to increase compression ratio significantly, although that was a problem in the 1920s. You can have a flake of carbon initiate pinging; but with modern fuels on older engines, a few full-bore bursts usually burns it off. Never seen so much carbon on a valve that it would reduce airflow. I sure have seen 1960s engines so full of OIL sludge that they had major problems... but that's not really a gasoline thing.
Apparently it can happen that fuel injectors lose capacity. On any modern ECU car, up to a point, this is corrected by the ECU applying longer injection pulses to get a happy tailpipe mix. When the nozzle gets real-clogged, the ECU can't make happy-mix at full throttle high RPM... then it will set the Check Engine light and you will fail your next smog-inspection.
But seems to me that clogged injectors are the Gas Company's Problem. Actually the way they make gasoline now the stuff is probably very-very-clean at the refinery. But crud sneaks in throughout the distribution process. Heck, I've seen used oil poured into the gasoline tanks; even done it myself. So gasoline company detergents are self-defense against their own distribution problems.
I would not cross the street to buy, or not-buy, Shell.
I do try to buy where the station appears to be tightly controlled by a major oil company. Sloppy dirty may be a little more likely at the no-name stations.
SSLtech
Well-known member
Direct-Injection intake valve-pair:
Also two more:
http://img185.imageshack.us/my.php?image=valve1td9.gif
and:
http://img291.imageshack.us/my.php?image=valve2pn3.gif
These are from a Turbo-Direct-inject motor with 22,000 miles on it. Apparently the combination of Positive Crankcase Ventilation and turbocharger oil seal blow-by is enough to cause a fine mist which likes to accumulate on the stems, as you can see. -In most engine designs (port-injection) this is washed off by the fuel. Detergents are a bonus, but Shell super-detergent gasoline won't do a THING for this. [edit:] I mean specifically in direct-inject motors where the valves never SEE raw fuel) [/edit]
Actually I'm investigating some sort of regular misting treatment (NOT seafoam or redex) which the manufacturers have apparently discovered can help keep tis stuff from getting TOO nasty.
Full thread form Fuel-stratified-charge direct-injection forum over at VWVortex, for anyone who is interested in the deposit issues.
http://forums.vwvortex.com/zerothread?id=4181184&uid=19827&dir=1
Keith
Also two more:
http://img185.imageshack.us/my.php?image=valve1td9.gif
and:
http://img291.imageshack.us/my.php?image=valve2pn3.gif
These are from a Turbo-Direct-inject motor with 22,000 miles on it. Apparently the combination of Positive Crankcase Ventilation and turbocharger oil seal blow-by is enough to cause a fine mist which likes to accumulate on the stems, as you can see. -In most engine designs (port-injection) this is washed off by the fuel. Detergents are a bonus, but Shell super-detergent gasoline won't do a THING for this. [edit:] I mean specifically in direct-inject motors where the valves never SEE raw fuel) [/edit]
Actually I'm investigating some sort of regular misting treatment (NOT seafoam or redex) which the manufacturers have apparently discovered can help keep tis stuff from getting TOO nasty.
Full thread form Fuel-stratified-charge direct-injection forum over at VWVortex, for anyone who is interested in the deposit issues.
http://forums.vwvortex.com/zerothread?id=4181184&uid=19827&dir=1
Keith
